Astm d 1312 93 (1998)

D 1312 – 93 (Reapproved 1998) Designation D 1312 – 93 (Reapproved 1998) Standard Test Methods for Apparent Free Phenols in Synthetic Phenolic Resins or Solutions Used for Coating Purposes 1 This stand[.]

Standard Test Methods for

Apparent Free Phenols in Synthetic Phenolic Resins or

This standard is issued under the fixed designation D 1312; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A

superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1 Scope

1.1 These test methods cover the determination of the

amount of apparent free phenol in synthetic phenolic resins or

solutions used for coating purposes The test method for

isolation of the free phenol applies to all the commonly used

resins except those containing p-phenyl-phenol Test Method A

applies to the simpler phenols up to and including the xylenols;

Test Method B applies to the common alkylated phenols

1.2 This standard does not purport to address all of the

safety concerns, if any, associated with its use It is the

responsibility of the user of this standard to establish

appro-priate safety and health practices and determine the

applica-bility of regulatory limitations prior to use.

2 Referenced Documents

2.1 ASTM Standards:

D 1193 Specification for Reagent Water2

3 Purity of Reagents

3.1 Reagent grade chemicals shall be used in all tests

Unless otherwise indicated, it is intended that all reagents shall

conform to the specifications of the Committee on Analytical

Reagents of the American Chemical Society, where such

specifications are available.3Other grades may be used,

pro-vided it is first ascertained that the reagent is of sufficiently

high purity to permit its use without lessening the accuracy of

the determination

3.2 Unless otherwise indicated, references to water shall be

understood to mean reagent water conforming to Type III of

Specification D 1193

ISOLATION OF FREE PHENOLS

4 Apparatus

4.1 Steam Generator.

4.2 Distillation Flask—A 500-mL Kjeldahl flask.

4.3 Condenser.

5 Reagents

5.1 Sodium Hydroxide Solution (100 g NaOH/L)—

Dissolve 100 g of NaOH [Caution] in water and dilute to 1 L

6 Procedure

6.1 Transfer 1 to 2 g of the sample, weighed to the nearest 0.01 g, to a 500-mL Kjeldahl flask Add 50 mL of water Lead steam from a steam generator through a T-trap and then through a tube extending to the bottom of the flask Take off the distillate through a second bent tube that extends just through the stopper of the flask and is attached to the top of an inclined long condenser Using a 1000-mL volumetric flask as a receiver, collect 900 mL of the distillate A small flame may be applied to the bottom of the Kjeldahl flask during distillation to maintain the volume of water constant If the distillate is clear, dilute to 1000 mL; if not, add several millilitres of NaOH solution to dissolve the insoluble phenols Determine the

apparent free phenol in accordance with Method A or B, as

required

N OTE 1—p-Phenylphenol is not completely isolated by this procedure.

TEST METHOD A—SIMPLER PHENOLS

7 Summary of Test Method

7.1 Free phenols are isolated by steam distillation, reacted with a measured excess of bromine, and the excess back-titrated with standard sodium thiosulfate solution

8 Apparatus

8.1 Iodine Flasks, 500-mL, glass-stoppered.

9 Reagents

9.1 Bromide-Bromate Solution—Dissolve 2.784 g of KBrO3

and 10 g of KBr in 1 L of water

1 These test methods are under the jurisdiction of ASTM Committee D-1 on Paint

and Related Coatings, Materials, and Applications and are the direct responsibility

of Subcommittee D01.33 on Polymers and Resins.

Current edition approved April 15, 1993 Published June 1993 Originally

published as D 1312 – 54 Last previous edition D 1312 – 56 (1987)e1.

2Annual Book of ASTM Standards, Vol 11.01.

3

Reagent Chemicals, American Chemical Society Specifications, American

Chemical Society, Washington, DC For suggestions on the testing of reagents not

listed by the American Chemical Society, see Analar Standards for Laboratory

Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia

and National Formulary, U.S Pharmacopeial Convention, Inc (USPC), Rockville,

MD.

9.2 Potassium Iodide Solution (100 g KI/L)—Dissolve 100

g of KI in water and dilute to 1 L

9.3 Sodium Thiosulfate, Standard Solution (0.1 N)—

Dis-solve 25 g of Na2S2O3·5H2O in 1 L of water Standardize

against iodine

9.4 Starch Indicator Solution—Dissolve 1 g of soluble

starch in 100 mL of boiling water and cool

10 Procedure

10.1 Pipet a 25-mL (or larger) aliquot of the distillate into a

shake, and add 10 mL of HCl (sp gr 1.19) Stopper quickly,

shake to mix thoroughly, and fill the gutter with water Let

stand 15 min (If the bromine color disappears during the

shaking, take a fresh aliquot, add double the amount of bromate

solution, and proceed as described.) Raise the stopper carefully

and add 10 mL of the KI solution Shake, and wash down the

stopper and walls of the flask Titrate with 0.1 N Na2S2O3,

solution using 1 mL of starch indicator at the end

10.2 Blank—Run a blank in exactly the same manner,

except to omit the test material

11 Calculation

11.1 Calculate the percentage of apparent free phenols

(Note 2), as follows:

where:

T 1 = Na2S2O3solution required for titration of the blank,

mL,

T = Na2S2O3solution required for titration of the sample,

mL,

N = normality of the Na2S2O3solution, and

W = sample represented in the aliquot used, g

N OTE 2—The cresols (CH3C6H4OH) and xylenols (CH3)2C6H3OH

have one or two reactive positions on the ring, depending on the isomer,

but their tendency to add more bromine as an addition product that is not

later removed by KI renders the exact extent of reaction uncertain Since

those materials are ordinarily used as mixtures in a resin-forming reaction,

it is convenient and sufficiently informative to express the amount found

as primary phenol.

12 Precision

12.1 The individual test results should not differ from the

TEST METHOD B—COMMON ALKYLATED

PHENOLS

13 Summary of Test Method

13.1 Free phenols are isolated by steam distillation, reacted

with a measured excess of iodine, and the excess back-titrated

with standard sodium thiosulfate solution

14 Apparatus

14.1 Iodine Flasks, 500-mL, glass stoppered.

15 Reagents

15.1 Iodine Solution—Dissolve 4.2 g of iodine in 15 g of a

saturated aqueous KI solution and dilute to 1 L

Dissolve 84 g of NaHCO3in water and dilute to 1 L

15.3 Sodium Hydroxide Solution (100 g NaOH/L)—

Dissolve 100 g of NaOH in water and dilute to 1 L

15.4 Sodium Thiosulfate, Standard Solution (0.1 N)—See

7.3

15.5 Starch Indicator Solution—See 9.4.

15.6 Sulfuric Acid (1+19)—Add slowly, while stirring, 1

volume of concentrated H2SO4[Caution] (sp gr 1.84) to 19 volumes of water

16 Procedure

16.1 Add 15 mL of NaOH solution to the steam distillate and dilute to 1 L Add 100 mL of water to a 500-mL iodine flask Pipet a 10-mL (or larger) aliquot of distillate into the flask (Note 3) and add 30 mL of the iodine solution Stopper

(1 + 19) to the flask and titrate with 0.1 N Na2S2O3solution to

a colorless end point, using 1 mL of starch solution as the indicator

N OTE 3—If the sample is pure p-phenylphenol, add 50 mL of the

NaHCO3solution to the flask before the sample is added to prevent the formation of color that interferes with the titration end point.

16.2 Blank—Run a blank in exactly the same manner,

except omit the sample

17 Calculation

17.1 Calculate the percentage of apparent free alkylphenols (Note 4) as follows:

where:

B = Na2S2O3 solution required for titration of the blank, mL,

V = Na2S2O3solution required for titration of the sample, mL,

N = normality of the Na2S2O3solution,

F = conversion factor

= 3.755 for p-tertiary-butyl phenol

= 4.106 for p-tertiary-amyl phenol

= 4.255 for p-phenyl phenol, and

S = sample represented in the aliquot used, g.

N OTE 4—The alkyl phenols form normal di-iodo compounds.

18 Precision and Bias

18.1 The individual test results should not differ from the

18.2 Bias—No bias can be determined since no standard

phenolic resin is available

19 Keywords

19.1 free phenol; iodine solution; phenolic resin

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